Root-associated mycobiota of Goodyera repens (Orchidaceae) populations from three Russian regions

Goodyera repens is an orchid, widespread and abundant in the coniferous forests of the northern hemisphere. Along with other members of Orchidaceae, in natural conditions it exists in obligate mycorrhizal symbiosis. Despite a long history of study, no data on the mycobiota associated with the root system of this species have been obtained for populations growing in Russia. It is therefore necessary to assess the entire diversity of fungal associates, including non-cultivated species, as well as to obtain quantitative characteristics and evaluate the geographic specificity of fungal communities. In this work, the mycobiota of the root system of G. repens growing in the Leningrad and Moscow Regions and Karachay-Cherkess Republic was analysed qualitatively and quantitatively for the first time using high-throughput sequencing. A total of 438 operational taxonomic units were identified, with the majority belonging to the subdivision Basidiomycota. The quantitative predominance of sequences of the genera Russula, Ceratobasidium, Piloderma, Mycena, and Tomentella was observed. Significant differences between fungal communities of soil and the root system of G. repens were established in all studied regions. The regional specificity of the taxonomic composition of the mycobiota was demonstrated. The taxa spectrum of the samples from Karachay-Cherkessia differed significantly from that of the Leningrad and Moscow Regions, while no notable difference was observed between the latter two. With regard to the distribution of ecological groups of fungi, no significant differences were found between the regions.